1. Field of the Invention
The present general inventive concept relates to a paper arranging device, and more particularly, to an electrophotographic image forming apparatus with the same.
2. Description of the Related Art
In general, an electrophotographic image forming apparatus prints a desired image by developing a latent image formed on a circumference of a photosensitive medium through optical scanning into a visible image by supplying toner onto the latent image, transferring the visible image onto paper, and fusing the visible image with the paper. The visible image is transferred onto and fused with the paper as the paper is transferred along a predetermined path. A paper arranging device arranges the paper to be moved toward the photosensitive medium so as to transfer the visible image onto a desired part of the paper. The paper arranging device is installed before the photosensitive medium in the predetermined path along which the paper is transferred.
FIGS. 1 and 2 are diagrams illustrating the operation of a conventional paper arranging device 10 to be installed in a conventional electrophotographic image forming apparatus. Referring to FIGS. 1 and 2, the paper arranging device 10 includes a driving roller 12, an idle roller 14, a photosensor 16, and a lever 18. The driving roller 12 and the idle roller 14 face each other, thus forming a nip N. The lever 18 is pressed and rotated by a tip Pa of moving paper P. The driving roller 12 is rotated by power generated by a motor (not shown), and the driving roller 12 is selectively connected to or disconnected from the motor through an electronic clutch (not shown).
Until the tip Pa of the paper P moving upward (see the arrows of FIGS. 1 and 2) arrives at the lever 18, the electronic clutch does not connect the driving roller 12 to the motor, thereby preventing the driving roller 12 and the idle roller 14 from being rotated. When the tip Pa of the paper P presses a first end 18a of the lever 18 upward, the lever 18 is rotated to turn a second end 18b of the lever 18 downward. Then, referring to FIG. 2, the second end 18b is separated from the photosensor 16, and the photosensor 16 senses the paper P. Next, the tip Pa of the paper P is curled by the nip N to arrange the paper P. The electronic clutch connects the driving roller 12 to the motor a predetermined time after the photosensor 16 senses the paper P, and the driving roller 12 and the idle roller 14 are rotated to transfer the paper P. A light scanning device (not shown) and a photosensitive medium (not shown) operate sequentially after a predetermined time after the electronic clutch operates so as to transfer an image onto a desired part of the paper P.
The conventional paper arranging device 10 sets times, i.e., an exposure time, when the light scanning device and the photosensitive medium begin to operate according to a time when the electronic clutch begins to operate. Thus, a delay in the operation of the electronic clutch increases an error between a substantial position and desired position of an image on the paper P.
FIGS. 3 through 5 are diagrams illustrating the operation of another conventional paper arranging device 50 to be installed in a conventional electrophotographic image forming apparatus. Referring to FIGS. 3 through 5, the paper arranging device 50 includes a driving roller 52, an idle roller 54, lower and upper levers 58 and 64, and lower and upper photosensors 56 and 62. The driving roller 52 and the idle roller 54 face each other, thus forming a nip N, and are installed between the lower and upper levers 58 and 64 and also between the lower and upper photosensors 56 and 62. The driving roller 52 is rotated by power generated by a motor (not shown), and selectively connected to or disconnected from the motor through an electronic clutch (not shown).
Until a tip Pa of paper P moving upward (see the arrows of FIGS. 3-5) arrives at the lower lever 58, the electronic clutch does not connect the driving roller 52 to the motor, thereby preventing the driving roller 52 and the idle roller 54 from being rotated. When the tip Pa of the paper P presses a first end 58a of the lower lever 58 upward, the lower lever 58 is rotated to turn a second end 58b of the lower lever 58 downward. Then, referring to FIG. 4, the second end 58b of the lower lever 58 is separated from the lower photosensor 56, and the lower photosensor 56 senses the paper P. Next, the tip Pa of the paper P is stopped and curled by the nip N, and thus, the paper P is arranged. The electronic clutch connects the driving roller 52 and the motor a predetermined time after the lower photosensor 56 senses the paper P, and the driving roller 52 and the idle roller 54 are rotated to transfer the paper P.
When the tip Pa of the paper P passes through the nip N and presses a first end 64a of the upper lever 64 upward, the upper lever 64 is rotated to turn a second end 64b of the upper lever 64 downward. Then, referring to FIG. 5, the second end 64b of the upper lever 64 is separated from the upper photosensor 62, and the upper photosensor 62 senses that the tip Pa of the conventional paper P has passed through the paper arranging device 50. A light scanning device (not shown) and photosensitive medium (not shown) begin to operate a predetermined time after the upper photosensor 62 senses the paper P, and transfer an image onto a desired part of the paper P.
The conventional paper arranging device 50 of FIGS. 3-5 sets times, i.e., an exposure time, when the light scanning device (not shown) and a photosensitive medium (not shown) begin to operate according to a time when the upper photosensor 62 senses the paper P. Therefore, unlike the paper arranging device 10 of FIGS. 1-2, an irregular delay in the operation of the electronic clutch does not remarkably increase an error between a substantial position and a desired position of the image on the paper P. However, as compared to the conventional paper arranging device 10 of FIGS. 1-2, the conventional paper arranging device 50 of FIGS. 3-5 requires an additional photosensor and an additional lever, thereby increasing manufacturing costs.